tagval Namespace Reference

Namespaces
namespace	detail

Classes
class	ClosedEnded
	CRTP base for tag-value kinds whose values are fixed at compile time. More...
struct	Entry
	Compile-time entry. More...
struct	KindEntryView
	Flattened, copy-friendly view of a single entry. More...
class	KindRegistry
	Program-wide index of every kind that opted in via TAGVAL_REGISTER_KIND. More...
class	KindView
	Type-erased handle to one registered kind. More...
class	OpenEnded
	CRTP base for tag-value kinds whose values are partly compile-time (Derived::values_t) and partly contributed by plugins via TAGVAL_EXTERN_ENTRY. More...
class	OpenEndedRegistry
	Runtime list of metadata pointers for a single OpenEnded kind. More...
struct	ParseError
	Returned via std::expected from try_of() when a code is not present. More...
class	TagValCell
struct	TagValDescriptor
	Runtime metadata describing a tag-value kind (e.g. More...
class	TagValError
	Common base exception. Catch this to handle any tagval-thrown error. More...
struct	TagValMetadata
	Runtime view of an entry's metadata. More...
class	UnknownCodeError
	Thrown by of() when a code is not present. More...
struct	Values
	Compile-time tuple of Entry types belonging to a single Owner. More...

Enumerations
enum class	KindCategory { Closed , Open }
	Which CRTP base a kind derives from. More...

Functions
template<typename E >
constexpr std::string_view	label_or_code () noexcept
	If the user declared an empty label, fall back to the code so that label() never returns an empty string for a valid entry.
template<typename E >
constexpr TagValMetadata	metadata_of () noexcept
template<typename T > requires std::derived_from<T, detail::TagValBaseTag>
void	to_json (::nlohmann::json &j, const T &v)
template<typename T > requires std::derived_from<T, detail::TagValBaseTag>
void	from_json (const ::nlohmann::json &j, T &v)
template<typename T > requires std::derived_from<T, detail::TagValBaseTag>
std::ostream &	operator<< (std::ostream &os, const T &v)
template<typename V >
constexpr auto	values_metadata_array ()
	Materialize the metadata array for a Values<...> list.
template<typename V >
constexpr auto	values_metadata_pointers ()
	Materialize an array of pointers to the pinned metadata_v<E> constants for a Values<...> list.

Variables
template<typename E >
constexpr TagValMetadata	metadata_v = metadata_of<E>()
	Pinned, per-entry TagValMetadata constant.

Enumeration Type Documentation

KindCategory

enum class tagval::KindCategory

strong

Which CRTP base a kind derives from.

Enumerator
Closed
Open

Function Documentation

label_or_code()

template<typename E >

constexpr std::string_view tagval::label_or_code ( )

constexprnoexcept

If the user declared an empty label, fall back to the code so that label() never returns an empty string for a valid entry.

metadata_of()

template<typename E >

constexpr TagValMetadata tagval::metadata_of ( )

constexprnoexcept

to_json()

template<typename T >
requires std::derived_from<T, detail::TagValBaseTag>

void tagval::to_json ( ::nlohmann::json &  j, const T &  v  )

inline

from_json()

template<typename T >
requires std::derived_from<T, detail::TagValBaseTag>

void tagval::from_json ( const ::nlohmann::json &  j, T &  v  )

inline

operator<<()

template<typename T >
requires std::derived_from<T, detail::TagValBaseTag>

std::ostream & tagval::operator<< ( std::ostream &  os, const T &  v  )

inline

values_metadata_array()

template<typename V >

constexpr auto tagval::values_metadata_array ( )

constexpr

Materialize the metadata array for a Values<...> list.

Used by ClosedEnded::all_values() to expose a constexpr metadata snapshot.

values_metadata_pointers()

template<typename V >

constexpr auto tagval::values_metadata_pointers ( )

constexpr

Materialize an array of pointers to the pinned metadata_v<E> constants for a Values<...> list.

Used by OpenEnded to seed Registry with stable addresses identical to those used by extern entries.

Variable Documentation

metadata_v

template<typename E >

constexpr TagValMetadata tagval::metadata_v = metadata_of<E>()

inlineconstexpr

Pinned, per-entry TagValMetadata constant.

Inline-variable templates are ODR-merged across translation units, so every TU sees the same address for metadata_v<E>. Registry stores pointers into this storage instead of copies, which keeps handle identity stable even when extern entries register after main() begins.